Bergsten, S. J. and Stewart, J. R. 2014. Measurement of the influence of low water availability on the productivity of Agave weberi cultivated under controlled irrigation. Can. J. Plant Sci. 94: 439-444. In recent years, research has focused on determining the potential of Agave to be utilized for bioenergy production due to its ability to grow in arid and marginal lands. However, little is known regarding its productivity under limited water conditions. Most Agave species can tolerate low soil-moisture levels, but it is unclear at what point productivity will be significantly constrained. Using an automated irrigation system under greenhouse conditions, we evaluated the effects of low to high volumetric water content (VWC) levels on biomass accumulation and nutrient uptake of a putative bioenergy crop, Agave weberi. Plants were exposed to four constant VWC levels (0.05, 0.12, 0.19, and 0.26 m³ m^-3). Shoot dry weight of plants in the 0.26 m³ m^-3 treatment was significantly higher than those in the 0.05 m³ m^-3 treatment, but not than those in the intermediate treatments. Both chlorophyll count and nutrient uptake decreased as VWC level decreased. Although plants were fairly productive under moderately dry soil conditions, it would be expected that over time, plants receiving high levels of irrigation would have greater growth than plants in dry soil moisture levels. However, similar yields between the well-watered and moderately dry treatments suggest that A. weberi should be further evaluated as a candidate energy crop in more long-term field trials.